Abstract The damping effect of the vertical baffles inside a liquid storage tank is studied in this paper. A numerical model based on the finite volume method is established and used to evaluate the accuracy of an analytical model developed to estimate the hydrodynamic damping caused by the vertical wall bounded baffles. For this purpose, several full scale baffled tanks with different aspect ratios are numerically analyzed. The numerical results were then used to validate the analytical model. The reduction in sloshing wave height caused by the baffles is estimated for selected tanks subjected to the seismic excitations. Finally, a simple procedure to estimate the reduction in sloshing amplitude due to the presence of baffles is proposed and validated using the time history numerical results.